We research the adsorption geometries graphene （Li-GR） before and after CO and electronic structures of pristine graphene （p-GR） and Li-doped adsorption by first-principles. The adsorption energies Ead of CO on p-...We research the adsorption geometries graphene （Li-GR） before and after CO and electronic structures of pristine graphene （p-GR） and Li-doped adsorption by first-principles. The adsorption energies Ead of CO on p-GR and Li-GR are calculated. The results demonstrate that Ead of CO on Li-GR is from -3.3 eV to -3.5 eV, meanwhile Q is up to 0.13e, which indicate that strong electrostatic attractions occur between CO and Li-GR, while CO is physically adsorbed on p-GR. The obvious accumulated charge in electron density difference and increasing carrier density suggest that the conductivity of Li-GR is improved considerably after CO adsorp- tion. An adsorption mechanism is also proposed. Our results provide a path to achieving CO sensors with high performance.展开更多
Based on SEM observance,the methods of low-temperature nitrogen and isothermal adsorption were used to test and analyze the coal samples of Hancheng,and pore structure characteristics of tectonic coals were discussed....Based on SEM observance,the methods of low-temperature nitrogen and isothermal adsorption were used to test and analyze the coal samples of Hancheng,and pore structure characteristics of tectonic coals were discussed.The results indicate that in the same coal rank,stratification and crack are well developed in cataclastic coal,which is mostly filled by mineral substance in the geohydrologic element abundance,results in pore connectivity variation.Granulated and mylonitic coal being of these characteristics,as develop microstructures and exogenous fractures as well as large quantity of pores resulted from gas generation and strong impermeability,stimulate the recovery of seepage coal,improve coal connectivity and enhance reservoir permeability.Absorption pore(micro-pore) is dominant in coal pore for different coal body structure,the percentage of which pore aperture is from 1 to 100 nm is 71.44% to 88.15%,including large of micro-pore with the 74.56%-94.70%;with the deformation becoming more intense in the same coal rank,mesopore enlarge further,open-end pores become thin-neck-bottle-shaped pores step by step,specific surface area of micro-pore for cataclastic coal is 0.0027 m 2 /g,while mylonitic coal increases to 7.479 m 2 /g,micro-pore gradually play a dominant role in effecting pore structural parameters.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 51372282,51072024 and 51132002the National College Students’Innovative and Entrepreneurial Training Program of Beijing Institute of Technology under Grant No201410007050
文摘We research the adsorption geometries graphene （Li-GR） before and after CO and electronic structures of pristine graphene （p-GR） and Li-doped adsorption by first-principles. The adsorption energies Ead of CO on p-GR and Li-GR are calculated. The results demonstrate that Ead of CO on Li-GR is from -3.3 eV to -3.5 eV, meanwhile Q is up to 0.13e, which indicate that strong electrostatic attractions occur between CO and Li-GR, while CO is physically adsorbed on p-GR. The obvious accumulated charge in electron density difference and increasing carrier density suggest that the conductivity of Li-GR is improved considerably after CO adsorp- tion. An adsorption mechanism is also proposed. Our results provide a path to achieving CO sensors with high performance.
基金funded by the National Major Research Program for Science and Technology of China (Nos. 2009ZX05062and 2011ZX05062-009)
文摘Based on SEM observance,the methods of low-temperature nitrogen and isothermal adsorption were used to test and analyze the coal samples of Hancheng,and pore structure characteristics of tectonic coals were discussed.The results indicate that in the same coal rank,stratification and crack are well developed in cataclastic coal,which is mostly filled by mineral substance in the geohydrologic element abundance,results in pore connectivity variation.Granulated and mylonitic coal being of these characteristics,as develop microstructures and exogenous fractures as well as large quantity of pores resulted from gas generation and strong impermeability,stimulate the recovery of seepage coal,improve coal connectivity and enhance reservoir permeability.Absorption pore(micro-pore) is dominant in coal pore for different coal body structure,the percentage of which pore aperture is from 1 to 100 nm is 71.44% to 88.15%,including large of micro-pore with the 74.56%-94.70%;with the deformation becoming more intense in the same coal rank,mesopore enlarge further,open-end pores become thin-neck-bottle-shaped pores step by step,specific surface area of micro-pore for cataclastic coal is 0.0027 m 2 /g,while mylonitic coal increases to 7.479 m 2 /g,micro-pore gradually play a dominant role in effecting pore structural parameters.
